/**
 * This file is part of Aion X Emu <aionxemu.com>
 *
 * This is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This software is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser Public License for more details.
 *
 * You should have received a copy of the GNU Lesser Public License
 * along with this software.  If not, see <http://www.gnu.org/licenses/>.
 */

package com.ibiaoke.common.utils;

/**
 * This class contains utilities that are used when we are working with classes
 *
 * @author SoulKeeper
 */
public class ClassUtils {

  /**
   * Return true if class a is either equivalent to class b, or if class a is a subclass of class b, i.e. if a either
   * "extends" or "implements" b. Note tht either or both "Class" objects may represent interfaces.
   *
   * @param a class
   * @param b class
   * @return true if a == b or a extends b or a implements b
   */
  public static boolean isSubclass(Class<?> a, Class<?> b) {
    // We rely on the fact that for any given java class or
    // primtitive type there is a unqiue Class object, so
    // we can use object equivalence in the comparisons.
    if (a == b) {
      return true;
    }
    if (a == null || b == null) {
      return false;
    }
    for (Class<?> x = a; x != null; x = x.getSuperclass()) {
      if (x == b) {
        return true;
      }
      if (b.isInterface()) {
        Class<?>[] interfaces = x.getInterfaces();
        for (Class<?> anInterface : interfaces) {
          if (isSubclass(anInterface, b)) {
            return true;
          }
        }
      }
    }
    return false;
  }

  /**
   * Checks if class in member of the package
   *
   * @param clazz class to check
   * @param packageName package
   * @return true if is member
   */
  public static boolean isPackageMember(Class<?> clazz, String packageName) {
    return isPackageMember(clazz.getName(), packageName);
  }

  /**
   * Checks if classNames belongs to package
   *
   * @param className class name
   * @param packageName package
   * @return true if belongs
   */
  public static boolean isPackageMember(String className, String packageName) {
    if (!className.contains(".")) {
      return packageName == null || packageName.isEmpty();
    } else {
      String classPackage = className.substring(0, className.lastIndexOf('.'));
      return packageName.equals(classPackage);
    }
  }
}
